Redirect output with multiple commands [duplicate]

Question

I'd like to redirect output from this command:

ps -eo pid,comm,cmd,start,etime | grep -i qtcreator > file.txt

When I try it, I've also output command grep -i example

2018 qtcreator       qtcreator                   08:11:50    01:05:00 <br>
5513 grep            grep -i qtcreator           09:16:50       00:00

How can I resolve this problem?

Answer 1

You can solve it by editing your command like this:

ps -eo pid,comm,cmd,start,etime | grep -i qtcreator | grep -v grep > file.txt

In this way you are exclude the ward grep from the result of the first grep

Answer 2

I think a more cleaner way would be to use pgrep with ps:

ps -p $(pgrep <program-name>)


[iahmad@localhost]$ ps -p $(pgrep sendmail)
PID TTY      STAT   TIME COMMAND
32373 ?        Ss     0:59 sendmail: accepting connections
32383 ?        Ss     0:00 sendmail: Queue runner@01:00:00 for    /var/spool/clientmqueue